A series of water-soluble fullerene derivatives, namely, e-C-60[C(COO-)(2)](2) (2), trans-3-C-60[C(COO-)(2)](2) (3), trans-2-C-60[C(COO-)(2)](2) (4), and e,e,e-C-60[C(COO-)(2)](3) (5) were probed in light- and radical-induced studies and compared to {(C-3(60))C(COO-)(2)}(n) clusters (1). Ground-state absorption spectra of 2-5, recorded in a concentration range between 1.0 x 10(-4) M and 5 x 10(-6) M, clearly speak against any appreciable deviation from the Lambert-Beer law. Picosecond-resolved photolysis gives rise to singlet excited state absorptions that closely resemble earlier observations for e-C-60[C(COOEt)(2)](2), tmns-3-C-60[C(COOEt)(2)](2), trans-2-C-60-[C(COOEt)(2)](2), and e,e,e-C-60[C(COOEt)(2)](3) in deoxygenated toluene solutions. The triplet lifetimes of 2-5, as measured by nanosecond-resolved photolysis, are typically around 40 mu s, similar to the triplet lifetimes of truly monomeric fullerene solutions. A strongly enhanced lifetime (by nearly 3 orders of magnitude) relative to {(C-3(60))C(COO-)(2)}(n) clusters (1) (tau = 0.4 mu s) indicates a truly monomeric appearance of these bis- and tris-functionalized fullerenes in aqueous solutions and confirms that micellar aggregation does, indeed, play only a minor role regarding the reactivity of these derivatives. Quenching experiments with diazabicyclooctane (DABCO), involving the triplet excited states of 2-5, yielded rate constants which reveal a strong dependence on the degree of functionalization. They vary between 7.4 x 10(7) M-1 s(-1) and 5.1 x 10(5) M-1 s(-1). This clearly indicates a substantial shift in the redox potential of the triplet excited state between pristine Coo and e,e,e-C-60[C(COO-)(2)](3) (5) AS a consequence of reductive quenching, the spectral region between 900 and 1100 nm shows the time-resolved growths of the pi-radical anion absorptions with maxima at 1040, 995, 880, and 1020 nm, for 2, 3, 4, and 5, respectively. They match the spectra generated by means of hydrated electrons (k = (0.75-3.4) x 10(9) M-1 s(-1)) and (CH3)(2). COH radicals (k = (0.9-2.2) x 10(8) M-1 s(-1)) in pulse radiolysis experiments.